In the exhaust gas from a diesel engine or the like, fine particles (particulate matter) are included. There is apprehension that release of these particles into the atmosphere may affect the environment. Therefore, in recent years, motor vehicles in which a diesel engine or the like is mounted are provided with a filter for removing fine particles in the exhaust gas (DPF: diesel particulate filter).
The filter is formed of ceramic or the like that is a porous body with a plurality of holes smaller than the fine particles. The filter prevents the fine particles from passing therethrough, to thereby collect the fine particles.
However, use of such a filter for a long time causes the collected fine particles to be accumulated, resulting in the clogging of the filter.
To prevent the clogging of the filter, a method such as shown in Patent Document 1 is employed in which a high-temperature gas is supplied to the filter, to thereby combust and remove the fine particles collected in the filter.
To be more specific, in Patent Document 1, a burner device is installed between a diesel engine and a filter. A mixture gas of an exhaust gas and a fuel is combusted to produce a high-temperature gas. The high-temperature gas is then supplied to the filter, to thereby combust fine particles.